Resilient strip mounting for plastic bag fabricator

ABSTRACT

A PLASTIC BAG FABRICATING, DISPERSING AND SEALING UNIT INCLUDES A LID HAVING MOUNTED ON IT A STRIP OF RESLIENT, NONADHERENT HEAT RESISTANT MATERIAL THAT ENGAGES A HEATING WIRE OF THE UNIT WHEN THE LID IS CLOSED, THE STRIP BEING AXIALLY RECEIVED IN A GROOVE THAT EXTENDS ALONG THE INNER FACE OF THE LID. OPENINGS FORMED AT EACH END OF THE GROOVE RECEIVE A ROD THAT EXTENDS THROUGH THE STRIP AND SECURES IT TO THE LID. AN APERATURE THAT EXTENDS THROUGH THE STRIP PARALLEL TO THE ROD PROVIDES THE STRIP WITH THE NECESSARY RESILIENCY.

M. FREEMAN 3,752,725

RESILIENT STRIP MOUNTING FOR PLASTIC BAG FABRIC/FOR Aug. 14, 1973 Filed April 25, 1971 vINVENTOR.

MAX FREEMAN Y M,M,DM* fir -J his ' 3,752,725 RESILIENT STRIP MOUNTING FOR PLASTIC BAG FABRICATOR Max Freeman, 75 Arleigh Road, Great Neck, NY. 11021 Filed Apr. 23, 1971, Ser. No. 136,725

Int. Cl. B32b 31/00 U.S. Cl.;156367 7 Claims ABSTRACT OF THE DISCLOSURE A plastic bag fabricating, dispensing and sealing unit includes a lid having mounted on it a strip of resilient, nonadherent .heat resistant material that engages a heating wire of the unit when the lid is closed, the strip being axially received in a groove that extends along the inner face of the lid. Openings formed at each end of the groove receive a rod that extends through the strip and secures it to the lid. An aperature that extends through the strip parallel to the rod provides the strip with the necessary resiliency.

BACKGROUND OF THE INVENTION This invention relates generally to plastic bag fabricating, dispensing and sealing units and, more specifically, to the lid of such a unit which mounts a strip of resilient, heat resistant material to engage the heating wire of the unit when the lid is closed.

A safe yet easily workable portable unit for making and sealing plastic bags of different sizes has been found to be a useful item. Such a unit, which operates by thermally sealing plastic sheeting, is shown and described,

in my application for US. Letters Patent Ser. No. 82,621, tiled Oct. 21, 1970. In the unit described in that application, the lid is formed with a groove that extends along the entire length of the edge of the lid. A strip of resilient, heat resistant material is shown affixed in the groove by a suitable adhesive and cooperates with the heating wire.

Difliculties have been encountered with the resilient strip. Since it must urge polyethylene sheeting against the heatingwire, the strip must not adhere to molten polyethylene and it also must be resistant to the high temperatures of the wire. Materials having these characteristics have been diflicult to aflix by adhesives to the lid. Thus, the property of not adhering to the molten polyethylene also causes the materials to resist most adhesives.

Moreover, strips that may be adhered by adhesive to the lid do not withstand long usage and must be replaced, a difficult and time-consuming operation when it involves removing the old strip, scraping the particlesof the strip from the groove and glueing in a new strip. It would be preferable to provide a substantially permanent resilient strip readily installed at the factory and yet easily removed and re-installed by a housewife if the strip inadvertently becomes damaged. 7

Moreover, the strip shown and described in my application Ser. No. 82,621 does not have as much resiliency and durability as desired for effective long-term operation of the unit. The unit is designed to accommodate a cartridge containing a Web of double-layered plastic film in the unit, the cartridge when in place closing a safety actuator switch. The unit can be stored without energizing the heating wire even though the resilient strip engages the wire when the lid is closed. This is accomplished by disposing a contact arm on the lid that does not close a sealing switch unless pressure is exerted on the lid for urging the contact arm against a sealing plunger. The strip, then, must be stiff enough so that it can SUMMARY OF THE INVENTION 7 There is provided, in accordance with the invention, a lid for a plastic bag fabricator whichhas a strip ofheat resistant material mounted along one edge to cooperate with the heating wire of the unit, the strip being mounted in such a way that it remains permanently in position and yet can be easily and quickly replaced.'The strip also has sufficient resiliency to enable safe storage and effective operation of the unit. V I

. More specifically, the strip is mounted in a groove that extends along the inner face of the lid near the front edge, which is the portion of the lid that cooperates with the heating wire, so that when the lid is closed the strip engages the wire.

The groove is closed by walls at each end and is preferably formed as the inner portion of a handle or gripper that projects from the outer face of the lid. The walls at the ends of the groove each have an opening that preferably is disposed above the outer surface of the lid. The openings coincide with a passage extending axially through the strip of heat resistant material. The strip is received within the groove, so that a rod can be passed through the openings from the outer side of the lid and extend through the strip and walls at each end of the groove for holding the strip in place. A guide channel provided ad jacent the outer side of one wall and a retaining channel adjacent the outer side of the other wall facilitates insertion of the rod and holds it in proper position.

It is apparent that the resilient strip can readily be installed on the lid in the factory and ordinarily such installation will be permanent. The strip is formed, for example, of a silicone rubber highly resistant to heat and also having the property of not adhering to molten polyethylene. Nevertheless, if it is necessary to replace a damaged strip, a housewife can readily remove the rod, take the old strip out of the groove, and then readily install a new strip.

The strip is shaped so that when it is received axially within the groove, a portion along one side projects from the inner face of the lid and engages the heating wire when the lid is closed. When the strip is not compressed and resting on the wire, the contact arm attached to the inner face is out of engagement with the plunger of the sealing switch. So that the strip is stig enough not to cause closure of the sealing switch and still resilient enough so that light pressure exerted on the lid will move the contact arm far enough to close the switch, the strip preferably has a second passage extending axially through it between the first hole and the side that engages the wire. The strip is formed with a sufficient amount of resilient material between the passage and the wire so that the strip will deform or flatten and enable the lid and the contact arm to move far enough to activate the circuit and energize the wire when light pressure is exerted on the lid.

Thus, there is provided in accordance with the invention a lid for a plastic bag fabricating, dispensing and sealing unit carrying an easily mounted resilient, non-adherent and heat resistant strip. Moreover, the strip can be readily and quickly installed at thefactory and, if necessary later, easily removed and replaced. The strip is specially designed to be resilient and yet stiff enough so that the unit can be safely stored while ready for use, and plastic bags can easily beformed by simply applying light pressure on the lid.

DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference maybe had to the following detailed description of an exemplary embodiment, taken in conjunction with the accompanying drawings, in which:

FIG. V1 is a perspective view of'a plastic bag fabricating, dispensing and sealing unit showing in particular the lid in its open position and having the strip of resilient, heat resistant material mounted along its inner face near the front edge so that the strip will engage the heating wire when the lid is closed;

FIG. 2 is a sectional view of the front portion of the lid, taken along line 2-2 in FIG. 1, showing the groove as being the inner portion of the handle or gripper of the lid, with the strip mounted in the groove;

FIG. 3 is a sectional view of the gripper looking toward the outer face'of theportion' of the lid shown in FIG. 2,

,taken alongiine -3 3 in FIG.,2, the center portion being 3,752,725- y i f i broken away to avoid repetition, the rod being shown as V projecting from and engaging the walls that form the ends of the groove;

FIG. 4 is a sectional view of the gripper and the strip, taken along line 4-4 in FIG. 3, the center portion being broken away to avoid reception, showing in particular the rod that holds the strip in place and the passage through the strip that provides it with the necessary resiliency.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Now, referring to FIG. 1, a plastic bag fabricating, dispensing and sealing unit is shown, being indicated generally by reference numeral 10, which operates essentially as described in my application for US. Letters Patent Ser. No. 82,621. The unit 10 comprises a main housing 12 and a lid 14 which is hinged to the side panels 16 of the housing 12. The lid 14 is hinged in a way that a slot 18 is formed between the inner face 20 of the lid 14 and the back panel of the housing 12 so that plastic bags can be passed through the slot 18 and sealed by the unit 10.

The housing 12 contains an electric circuit (not shown) that is activated when the lid 14 is closed far enough so that the actuator or contact arm 22, which projects from the inner face 20 of the lid 14, engages and closes a sealing switch (not shown) which is part of the circuit. This energizes and heats the wire 24. When pressure is exerted on the lid 14, plastic bags can be formed from the doublelayered web of plastic film contained in the housing 12, the leading edge of which is shown in FIG. 1 and designated by reference numeral 26. Plastic bags, even those not fabricated by the unit 10, can also be sealed shut by placing the open edge adjacent the wire 24 annd closing the lid 14 far enough to activate the circuit, as descirbed above.

The unit 10 operates on the so-called impulse method of sealing where heat and pressure are applied simultaneously to melt and thereby seal an edge of the double-layered plastic film and, at the same time, to sever the portions 'of the web disposed on either side of the heating wire 24. The most satisfactory arrangement for accomplishing these results has been found to have the heating wire 24 extend along the upper front edge of the main housing 12 of the unit 10, a strip of heat resistant material being interposed between the housing 12 and the wire 24.

The lid 14 is designed and attached in such a way that the needed pressure for fabricating the bags can be easily applied. For preventing melted plastic from sticking to the lid 14 and to provide an easily workable and safe way for simultaneously heating the wire and applying the necessary pressure, a strip of resilient, nonadherent and heat resistant material 28 is mounted along the inner face 20 4 of the lid 14 near the front edge so that when the lid-:14 is closed, the strip 28 engages the wire 24.

As best shown in FIGS. 2 and 4, the strip 28 is received in a groove 30 which opens onto the inner face 20 of the lid 14 and extends along it near the front edge. As shown in this preferred embodiment of the invention, the groove 30 does not extend along the entire length of the lid 14 but it terminated by walls 32, the groove 30 forming the inner portion of a handle or gripper 34 which projects from the outer face 35 of the lid 14. The ends of the gripper 34, which are disposed above the outer face 35 of the lid 14, are shown as forming the end Walls 32 of the groove30. Q

As best shown in FIGS. 3 and 4, each of the walls 32 has an opening 36 passing through it, which coincides with a passage'38 that extends through the strip 28 (see FIG. 2), so that a rod 40 can be inserted through the openings 36 and 38 to engage the strip 28 and the walls 32 for holding the strip 28 in place on the lid 14. The groove 30 can have a rib 42 projecting along its back wall 44; which abuts the strip 28 (see FIG. 2), so that the gripper 34-is sufiiciently large to be easily grasped but withouthaving to use additional material in forming the gripper 3401 the strip 28.

Additionally, as shown in FIGS. 3 and 4, an open guide channel 46 and a closed retaining channel 48 are formed on the outer face 35 of the lid 14 adjacent the openings 36 in the walls 32. These channels 46 and 48 facilitate insertion of the rod 40 into the openings 36 and 38, permitting it to be passed through the openings the proper distance so that the rod 40 can be easily inserted for securely holding the strip 28 is place.

By mounting the strip 28 on the lid 14 as described above, its installation and replacement are quick and simple operations. To install the strip 28, all one need do is insert the rod 40 through openings 36 and the strip passage 38. To remove the strip,'the procedure is merely reversed.

The strip 28 is formed of a resilient and nonadherent material such as, for example, a silicone rubber which is resistant to heat at temperatures used to form the plastic bags and to which the plastic used to form the bags does not adhere when melted. This latter property has prevented secure fastening of the strip in the channel by an adhesive. The strip 28 must be stiff enough to engage and rest on the wire 24 when the lid 14 is closed (such as when the unit 10 is not in use) without the contact arm 22 moving sufliciently'to close the sealing switch and energlze the wire 24. However, the strip 28 must be resilient enough so that when light pressure is applied to the lid 14 (by pushing down on the gripper 34), the front edge of the lid 14 and the contact arm 22 will move far enough to close the sealing switch so that-a plasticbag can be formed or sealed.

To provide the strip 28 with the necessary resiliency, a second passage 49 is formed in the strip 28, which extends through it between the passage 38 and the outer side of the strip 28 that engages the wire 24 when the lid 14 is closed. As best shown in FIGS. 2 and 4, the outer side of the strip 28 is rounded to conform to the shape of the passage 49 and there is suflicient material between the passage 49 and the wire 24 so that the strip 28 has the optimum resiliency to operate the unit 10.

By providing the passage 49 in the strip 28, when the strip 28 is engaging the wire 24 and pressure is applied to the lid 14, the portion of the strip 28 through which the passage 49 passes will deform or flatten, thereby causing the contact arm 22 to move a suflicient distance to close the sealing switch and heat thewire 24. When the pressure is released, the strip 28 will reassume the shape shown in FIGS. 3 and 4, de-activating' the electric circuit. 7

Thus, there is provided in accordance with the invention a mounting for a resilient, heat resistant strip on the lid of a plastic bag fabricating, dispensing and sealing unit. The embodiment of the invention as described above is intended to be merely exemplary, and those skilled in the art will be able to make variations and modifications, without departing from the spirit and scope of the invention as set forth in the appended claims, and those variations and modifications are intended to be within the scope of the appended claims.

I claim:

1. In a plastic bag fabricator of the type that has a main housing, a heating wire extending along a portion of the housing, the wire being connected to an electric circuit contained in the housing, the circuit including a normally open switch, a lid hinged on the housing, a strip of resilient, heat resistant material attached to the inner face of the lid and positioned so that when the lid is closed, the strip engages the wire, and the lid further including an actuator projecting therefrom and cooperating with the switch so that when the lid is closed a predetermined distance the actuator closes the switch thereby energizing the wire, the improvement comprising a pair of rod retaining means spaced apart on the lid, each of the retaining means including an opening, the strip being positioned on the lid between the retaining means and having a first passage extending axially therethrough coinciding with the openings in the retaining means, and a rod passing through the openings and the passage and engaging the retaining means for securing the strip to the lid.

2. The improvement according to claim -1, in which the strip is formed of a heat resistant silicone rubber that is non-adherent to molten polyethylene.

3. The improvement according to claim 1, further comprising a groove extending along the inner face of the lid, a gripper projecting from the outer face of the lid, the groove forming the inner portion of the gripper, the retaining means at least partially forming the ends of the gripper and projecting above the outer face of the lid so that the openings therein are above the outer face, and the strip being received in the groove and dimensioned so that a portion projects from the inner face of the lid for engaging the heating wire when the lid is closed.

4. The improvement according to claim 3, in which one of the retaining means includes means forming an open guide channel for the rod on the outer face of the lid, and the other retaining means includes means forming a closed retaining channel for the rod on the outer face of the lid.

5. The improvement according to claim '1, wherein the strip further includes a second passage extending therethrough between the first passage and the side of the strip that engages the heating wire when the lid is closed, the strip being stiff enough so that when the lid is closed the strip will rest on the heating wire without moving far enough to enable the actuator to close the switch, and the strip being resilient enough so that when light pressure is applied to the lid the actuator will move to close the switch for energizing the heating wire.

6. The improvement according to claim 5, in which the strip is formed of a heat resistant silicone rubber that is non-adherent to molten polyethylene.

7. In a plastic bag fabricator of the type that has a main housing, a heating wire extending along a portion of the housing, the wire being connected to an electric circuit contained in the housing, the circuit including a normally open switch, a lid hinged on the housing, a strip of resilient, heat resistant material attached to the inner face of the lid and positioned so that when the lid is closed, the strip engages the wire, and the lid further including an actuator projecting therefrom and cooperating with the sWitch so that when the lid is closed a predetermined distance the actuator closes the switch thereby energizing the wire, the improvement comprising a groove extending along the inner face of the lid, a gripper projecting from the outer face of the lid, the groove forming the inner portion of the gripper, each of the ends of the groove projecting above the outer face of the lid and having an opening therein that is disposed above the outer face of the lid, the strip having a first passage extending therethrough coinciding with the openings in the ends of the groove when the strip is received in the groove, a rod passing through all of the openings in the passage and engaging the ends of the groove and the strip for securing the strip to the lid, a portion of the strip projecting from the inner face of the lid for engaging the heating wire when the lid is closed when the strip is so secured, and the strip further including a second passage extending therethrough between the first passage and the side of the strip that engages the heating wire when the lid is closed, the portion of the strip projecting from the inner face of the lid being stiif enough so that when the lid is closed the strip will rest on the heating wire without moving far enough to enable the actuator to close the sealing switch, and the strip being resilient enough so that when light pressure is applied to the lid the actuator will move far enough to close the switch for energizing the heating wire.

References Cited UNITED STATES PATENTS 2,334,077 11/1943 Farrel 20658 2,679,280 5/ 1-954 Marsh 156515 2,857,046 10/ 1958 Klein 20658 3,121,542 2/1964 Van Dyke et al 20652 R 3,166,187 1/1965 Arajo 206-58 3,354,017 11/1967 Lazear et a1 156-515 3,452,511 7/ 1969 Hoffier 83-171 3,459,083 8/1969 Bennis 83171 3,463,371 10/ 1969' Geiger 20658 NORMAN G. TO-RCHIN, Primary Examiner E. C. KIMLIN, Assistant Examiner US. Cl. X.R. 

